Ferroelectric random access memory capacitor and method for manufacturing the same

Abstract

The method for manufacturing an FeRAM capacitor with a merged top electrode plate line (MTP) structure is employed to prevent a detrimental impact on the FeRAM and to secure a reliable FeRAM device. The method includes steps of: preparing an active matrix obtained by a predetermined process; forming a first conductive layer, a dielectric layer and a second conductive layer on the active matrix in sequence; forming a hard mask on the second conductive layer; patterning the second conductive layer, the dielectric layer and the first conductive layer by using the hard mask, thereby forming a vertical capacitor stack, a width of the capacitor stack being larger than that of the storage node contact; forming a second ILD embracing the capacitor stack; planarizing the second ILD till the top face of the hard mask is exposed; removing the hard mask to form an opening above the top electrode; and forming a plate line of which a width is larger than that of the capacitor stack.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a semiconductor device and a method for manufacturing the same; and, more particularly, to a ferroelectric random access memory (FeRAM) capacitor having a merged top electrode plate line (MTP) structure therein and a method for manufacturing the same. DESCRIPTION OF THE PRIOR ART [0002] With the recent progress of film deposition techniques, researches for a nonvolatile memory cell using a ferroelectric thin film have increasingly been developed. This nonvolatile memory cell is a high-speed rewritable nonvolatile characteristic utilizing high-speed polarization / inversion and residual polarization of a ferroelectric capacitor thin film. [0003] Therefore, a ferroelectric random access memory (FeRAM) where a ferroelectric material such as strontium bismuth tantalate (SBT) and lead zirconium titanate (PZT) is increasingly used for the capacitor thin film in place of a conventional silicon oxide film or a silicon nitride film...

AI Technical Summary

Benefits of technology

[0018] It is, therefore, an object of the present invention to provide a ferroelectric random access memory (FeRAM) capacitor having a merged top electrode plate line (MTP) structure therein by employing a one-step etching for forming a vertical capacitor stack, thereby enhancing a ferroelectric property and preventing a crack in the ferroelectric layer.

[0019] It is another object of the present invention to provide a method for manufacturing the FeRAM device with the MTP structure by employing a one-step etching for forming a vertical capacitor stack, thereby enhancing a ferroelectric property and preventing a crack in the ferroelectric layer.

Problems solved by technology

However, the conventional method for manufacturing the FeRAM capacitor as aforementioned suffers from several shortcomings.

In the long run, a ferroelectric property of the FeRAM capacitor becomes deteriorated.

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